Events of Red Dead Redemption

Zubieta appeared in many missions that take place in Nuevo Paraiso. In the mission An Appointed Time Zubieta and his soldiers captured Abraham Reyes and were preparing to execute him until Marston arrives. John threatened to kill Raul and his soldiers if they didn't let Reyes go. But before Raul can answer, Luisa Fortuna charges the major with a Knife. She is shot three times in the chest and falls dead to the ground. In rage, Marston kills Zubieta's soldiers and Zubieta challenges Marston to a duel, in which Zubieta is killed.

His character model is not seen again in El Presidio after the end of the Nuevo Paraíso chapter.

Undead Nightmare

In the Undead Nightmare, Zubieta appears alive and well, defending Chuparosa and El Presidio. There is no unique interaction between him and Marston. He still arms himself with his Schofield Revolver seen in the base game.